ES2971608T3 - Potash powder granulation procedure - Google Patents

Abstract

According to some embodiments, provided herein is a potash powder granule comprising a binder selected from the group including fly ash, sodium silicate, potassium silicate and starches, wherein said potash powder comprises particles with a size between 0.001 and 0.5 mm. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Potash powder granulation procedure

Fields of invention

The present invention relates to the field of fertilizers, specifically to the production of potash granules from potash powder.

Background of the invention

To grow properly, plants need nutrients (nitrogen, potassium, calcium, zinc, magnesium, iron, manganese, etc.) that can normally be found in soil. When some soil elements are missing, fertilizers are added to achieve desired plant growth as they can enhance plant growth.

This plant growth is obtained in two ways, the traditional one being additives that provide nutrients. The second way in which some fertilizers act is to enhance the effectiveness of the soil by modifying its water retention and aeration. Fertilizers typically provide, in varying proportions, three main macronutrients:

nitrogen (N): leaf growth;

phosphorus (P): development of roots, flowers, seeds, fruits;

potassium (K): strong stem growth, water movement in plants, promoting flowering and fruit production;

three secondary macronutrients: calcium (Ca), magnesium (Mg) and sulfur (S);

micronutrients: copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn), boron (B), and occasionally silicon (Si), cobalt (Co) and vanadium (V) are important. plus rare mineral catalysts.

The most reliable and effective way to match nutrient availability to plant requirements is by controlling their release into the soil solution, using slow-release or controlled-release fertilizers. Both slow release fertilizers (SRF) and controlled release fertilizers (CRF) deliver nutrients gradually. However, slow-release fertilizers and controlled-release fertilizers differ in many ways: the technology they use, the release mechanism, longevity, release control factors, and more.

Solid fertilizers include granules, beads, crystals and powders. A bead fertilizer is a type of granular fertilizer that is almost spherical produced by solidifying droplets in free fall in air or a fluid medium. Most controlled release fertilizers (CRF) used in commercial nurseries are bead fertilizers that have been coated with sulfur or a polymer. These products have been developed to allow a slow release of nutrients in the root zone throughout the entire crop development.

During the manufacture of various types of dry fertilizers, dust is usually formed.

Compaction can often be used to utilize the dust formed in such a process, however, compaction is a complicated operation that usually requires the use of high intensity compactors. Document EP0488199 refers to a process for granulating potassium salts, and in particular K<2>SO<4>and/or KCl.

Document US2011218102 refers to water-dispersible potash of organic origin.

DE102007049182 relates to a processing method for crude potassium salts of polyminerals with a complicated mineral composition and high to very high contents of clay and insoluble compounds. Document CN104355778 relates to a potassium fertilizer, and more particularly to a potassium fertilizer granule and a granulation method thereof, and belongs to the field of slow release granular potassium fertilizer.

WO02066402 relates to a method for producing a slow release fertilizer and a slow acting strength fertilizer.

Document GB2032903 refers to a process for producing a potassium silicate fertilizer soluble in citric acid at high yield and with high thermal efficiency, and an apparatus for carrying out said process. Document US2017129823 refers to a granulation procedure by pressing salts and mixtures of non-ductile salts, especially sulfate-type mineral salts, such as kieserite (MgSO<4>.H<2>O), langbeinite (K<2> SO<4,>2MgSO<4>), polyhalite (K<2>SO<4>.MgSO<4,>2CaSO<4,>2H<2>O) or arcanite (K<2>SO<4>) or mixtures of these salts.

CN 107141 052 A relates to fertilizer granules comprising potassium chloride, potassium sulphate and fly ash.

Summary of the invention

According to the invention, there is provided herein a granule according to claim 1. According to the invention, there is provided herein a granule comprising potash powder and a binder; wherein said binder is fly ash.

According to the invention, the potash powder comprises particles with a size between 0.001-0.5 mm.

According to the invention, the binder is fly ash in a concentration of between 0.5-8% w/w. Some additional silicate-containing binders are preferable as they include elements that may be beneficial to the plant, beyond their binding properties, such a binder may further include, for example, glass potassium metasilicate, bentonite and the like.

Glass potassium metasilicate can be in a concentration of between 0.5-5% w/w.

Bentonite can be in a concentration of between 0.5-5% w/w.

The starch can be in a concentration of between 0.5-5% w/w.

According to some embodiments, the granule may further include additives selected from the group including minerals, binders, microelements, macroelements, water, or a combination thereof.

According to the invention, the granules also comprise polyhalite as an additive in a concentration of between 0.5 and 6% w/w.

According to claim 2, a procedure is provided herein for the preparation of the granule of the invention comprising: preparation of fly ash as a binder; transferring said binder and polyhalite as an additive to a mixer and homogeneously mixing said binder and additive with a powdered potash feed to produce initial granules; transferring said initial granules to an agglomerator to produce agglomerates with a size ranging between 0.5 mm and 8 mm; transferring said agglomerates to a fluidized bed (FB) classifier to produce classified agglomerates; Dry the sorted agglomerates in a dryer and transfer them to a sieve to produce particles in 3 different size ranges:

1. oversized particles having a diameter size of more than 6 mm;

2. undersized particles having a diameter size below 1 mm;

3. particles of desired size having a diameter size between 1 and 6 mm;

introducing said undersized particles back into said powder feed; and crushing said oversized particles to provide crushed particles wherein said crushed particles are then sieved through the sieve.

According to some embodiments, the preparation of the binder may include the following steps: heating of binder, mixing, grinding, activation, dissolving and curing.

According to some embodiments, the desired size particles may have a diameter size of between 2-4 mm, for example, which is beneficial for both the release rate of the fertilizer and for transportation purposes. Also described is a method of granulating powdered fertilizer, for example, powdered potash, comprising pre-mixing the powder in a high shear mixer, drum, agglomerator and/or a combination thereof to produce a potash blend.

The method may include adding additives, for example, minerals, dry and wet organic and inorganic binders, dilute binders, microelements, macroelements, cold water, hot water, steam or a combination thereof.

The method may include adding the combination to a granulator in order to produce granules from powdered potash.

The granules formed in the granulator may be dried, for example, in a drum dryer or fluid bed dryer or combination thereof and optionally sieved after or before drying to provide Potash granules of desired size.

Detailed description of the invention

Provided herein is a granule comprising potash powder and a binder, wherein said binder is fly ash.

An additional binder may be selected from the group including sodium silicate, potassium silicate, oxides such as calcium oxide, metakaolin, zinc oxide and/or iron oxide and starches. Fly ash is the binder of the invention since it acts as a geopolymer that forms very strong binder bridges between the particles of powder material.

Potash powder comprises particles with a size between 0.001-0.5 mm.

In the industrial process of handling potash, it can be extremely difficult and/or complicated to use potash particles having a size of less than 0.5 mm (also referred to herein as "powdered potash"). Such particles do not adhere easily and are usually discarded during the potash handling procedure.

Potash powder particles are characterized by having a smooth surface and a fairly cubic shape. During a granulation procedure, there are often large spaces between the potash powder particles, making adhesion very difficult. The complicated structure of the powdered potash particles allows only a few points of contact between the particles and, consequently, the granular material provides particles that have very weak adhesion.

Also described is a method for granulating powdered potash, comprising pre-mixing the powder in a high shear mixer drum, agglomerator and/or a combination thereof to produce a potash blend.

The method may include adding additives, for example, dry and wet organic and inorganic binders, microelements, macroelements, cold water, hot water, steam or a combination thereof.

The method may include adding the combination to a granulator in order to produce powdered potash granules. The granulator may include any suitable granulator including, for example, high shear granulator, agglomerator, drum granulator and the like.

The granules formed in the granulator can be dried, for example, in a drum dryer or fluid bed dryer and optionally sieved to provide potash granules of desired size.

The method described herein may include an efficient procedure to use the maximum amount of potash powder and reduce product waste.

The powdered potash granule of the present invention may further comprise one or more binders and/or additives, for example, to improve the adhesion, rheology and/or strength of the granule wherein the binders and/or additive may be selected from the group which includes bentonite, for example, in a concentration of between 0.5-5% w/w; starch, for example, in a concentration of between 0.5-5% w/w; oats, for example, in a concentration of between 0.5-5% w/w. Fly ash, as a binder of the invention, can preferably be in a concentration of between 0.5-5% w/w.

The granule of the present invention comprises fly ash in a concentration of between 0.5-8% w/w.

The granule may include a combination of additional binders and/or additives, including, for example, a combination of fly ash and NaOH, for example, in a concentration of between 0.5-5% w/w; fly ash and 0-2% w/w Ca (OH)2; fly ash and 0-4% w/w CaO or 0-6% w/w MgO; fly ash and 0-2% w/w ZnO; fly ash and 0-2% w/w FeO; fly ash and 0-6% w/w SSP (single superphosphate), TSP (triple superphosphate), optionally with water glass; fly ash and 0-5% wax, e.g. residual wax; fly ash and 0-10% w/w PEG, 2.5% potassium silicate, 2% calcium oxide. The granule comprises at least fly ash as a binder at between 0.8% w/w and polyhalite as an additive at between 0.5-6% w/w.

The granule size distribution may be between 0.5-8 mm, preferably between 2-4 mm. Any oversized particles can be subjected to a grinding process, and the crushed particles can be recirculated back to the granulator along with any undersized particles, for example, as explained in detail with respect to Figure 1.

The granules of the present invention may have preferred characteristics, for example, compared to granules produced by a compaction process. Preferred characteristics may include, for example, better rheology, reduced dust formation during transport, reduced bulking and/or aggregation effect.

Reference is made to Figure 1 which illustrates a method of preparing the granule of the present invention (“the method”).

As shown in Figure 1, the method includes the preparation of a binder 102, which may include the following steps: heating of binder, mixing, grinding, activation, dissolving and curing and/or any other suitable action that may prepare a binder to be mixed with powdered potash.

The prepared binder may optionally be further mixed with water at binder addition step 104. The binder is transferred to a mixer 106 and homogeneously mixed with a powder feed 108 to produce initial granules (also referred to herein as document “combination”).

The mixer 106 may include any suitable mixer that can allow homogeneous mixing of the powder feed with a binder and/or water, including, for example, high shear mixer, drum, a Plowshare® mixer, paddle mixer, powder mixer. pins and the like.

The initial granules are transferred to an agglomerator 112, in which additional water can be added if required according to step 110. According to some embodiments, additional additives can be added to the agglomerator 112, including, for example, additional binders, micro or macro elements or combinations. thereof. The products from agglomerator 112 are agglomerates with a size ranging between 0.5 mm and 8 mm. The agglomerates are then transferred to a fluidized bed (FB) classifier 114 to optionally separate oversized particles (also referred to herein as “OS”), and any undersized particles (also referred to herein as “US”). It can be recirculated to the mixer or agglomerator.

The sorted agglomerates are then dried in a dryer 116 and transferred to the sifter 118.

According to some embodiments, any powder that is formed during the drying process of dryer 116 can be transferred back to powder feed 108.

Particles in 3 different size ranges are produced from sieve 118:

1. oversized particles 126 (also referred to herein as “OS”) having a diameter size of more than 6 mm;

2. undersized particles 124 (also referred to herein as “US”) having a diameter size below 1 mm;

3. particles of desired size having a diameter size of between 1 and 6 mm, preferably between 2 and 4 mm.

Undersized particles 124 that may form while passing through the sieve 118 are introduced back into the powder feed 108.

The oversized particles 126 pass through at least one grinding process to be ground to a desired size by a grinder 120 and then the resulting crushed particles are sieved once again through the sieve 118.

According to some embodiments, particles of desired size are subjected to product sieving in step 122.

According to some embodiments, any dust that may form during product sieving 122 can be introduced back into the process, for example, into the powder feed 108.

Potash granules can provide superior characterization as fertilizers such as microelement addition, coated potash and be beneficial in the use of potash powder.

Example 1 (not according to the invention)

2000 g of KCl powder mixed with 1.2% ZnO, 14% water is added using an Eirich type mixer for 2.5 minutes at 4000 rpm. Add 4% fly ash, 2% NaOH and mix at 1000 rpm for 1 minute, and 5 minutes at 500 rpm. An additional 25 g of water is added during the granulation procedure. The granules are dried at 180 °C for 20 minutes.

The yield was 81%. The strength of the granules was 3.1 kg per granule and 2.6 kg per granule after 24 h at 79% humidity.

Example 2 (not according to the invention)

Like example 1, with 1.2% Ca(OH)<2>.

The yield was 73%. The strength of the granules was 3.1 kg per granule and 2.6 kg per granule after 24 h at 79% humidity.

Example 3 (not according to the invention)

As in example 1, with 1% Ca(OH)<2>and initial mixing for 4 minutes.

The yield was 64%. The strength of the granules was 2.8 kg per granule and 1.5 kg per granule after 24 h at 79% humidity.

Example 4 (not according to the invention)

Like example 3, with pre-mixing for 4 minutes.

The yield was 73%. The strength of the granules was 2.4 kg per granule and 1.2 kg per granule after 24 h at 79% humidity.

Example 5 (not according to the invention)

15 kg of potash powder, 5% fly ash and 14% water are mixed using Plowshare device at 350 rpm for 35 minutes.

The yield was 35%. The strength of the granules was 2.2 kg per granule and 1 kg per granule after 24 h at 79% humidity.

Example 6 (not according to the invention)

25 kg of potash powder, 5% fly ash and 14% water are mixed using Plowshare device at 350 rpm for 15 minutes.

The yield was 26%. The strength of the granules was 2.5 kg per granule and 0.5 kg per granule after 24 h at 79% humidity.

Example 7 (not according to the invention)

Like example 5, with 8% solid phosphogypsum. The strength of the granules was 2.4 kg per granule and 1 kg per granule after 24 h in humidity.

Example 8 (not according to the invention)

Like example 7, with 8% phosphogypsum in suspension. The strength of the granules was 1.7 kg per granule and 1.5 kg per granule after 24 h in humidity.

Example 9 (not according to the invention)

Like example 5, with KCl and 4% fly ash. The strength of the granules was 2.9 kg per granule and 1.4 kg per granule after 24 h in humidity.

Example 10 (not according to the invention)

Like example 1, with 3% water glass, 3% fly ash. The strength of the granules was 2.2 kg per granule and 2.6 kg per granule after 24 h in humidity.

Example 11 (not according to the invention)

As example 10, with 3% water glass, 3% fly ash, 0.1% FeO and 5% SSP as coating material. The strength of the granules was 2.0 kg per granule and 2.1 kg per granule after 24 h in humidity.

Example 12 (not according to the invention)

30 kg of potash powder is crushed into powder, 75% < 110 pm, 14% < 44 pm, and transferred to a rotary inclined mixing machine with high-speed eccentric mixing rotation.

The potash is mixed at elevated temperature, for example at about 80 degrees Celsius.

Dry (dry mixing stage) and liquid (wetting stage) binders and additives are added and the mixture is mixed for an additional time after each stage.

The mixture is then transferred to a rotating and inclined disc agglomerator for granulation (granulation stage).

The granulated product is transferred to a wet sieve to result in granules with a size between 2-4 mm. Undersized product is returned to the mixer, and oversized product is sent to a crusher and back to the process. The granules are dried in two stages at 70 degrees and then at 120 degrees. The product is sieved to between 2-4 mm and can be coated with a hydrophobic agent.

Example 13 (not according to the invention)

30 kg of potash powder, 75% < 110 pm, 14% < 44 pm, are mixed at a rotor speed of 5 m/s and container speed of 1.4 m/s for 18 minutes at 80 degrees.

In the dry mixing step, dry additives and binder: 750 g of calcium oxide and 27.5 g of iron oxide are added and mixed for an additional 1 minute at a rotor speed of 9 m/s.

In the wetting stage, liquid additive and binder are added: 7.5 kg of water at 60 degrees and 0.9 kg of potassium silicate at 86 degrees are added and the mixture is mixed for 0.5 minutes.

The mixture is then transferred to the agglomerator and granulated for 2 minutes at a rotor speed of 27 m/s and 86 degrees. The granules are sieved to obtain 2-4 mm granules.

Undersized material is returned to the mixer and oversized material is transferred to the crusher. The granules of between 2-4 mm are dried in two phases: at 70 degrees and 110 degrees.

Example 14 (not according to the invention)

30 kg of potash powder, 75% < 110 pm, 14% < 44 pm, are mixed at a speed of 5m/s and a container speed of 1.4 m/s for 18 minutes at 80 degrees. Additives and dry binders are added: 450 g of calcium oxide, 300 g of fly ash and 27.5 g of iron oxide are added and mixed for an additional 1 minute at a rotor speed of 9 m/s.

Liquid additives are then added to the wetting stage: 8 kg of water at 60 degrees and 0.9 kg of potassium silicate at 86 are mixed for 0.5 minutes and granulated for 1.5 minutes at a rotor speed of 27 m/s at 80 degrees.

The granules are then sieved to obtain 2-4 mm granules.

Any undersized material is returned to the mixer and any oversized material is returned to the crusher.

The resulting granules of between 2-4 mm are dried in two phases: at 70 degrees and 110 degrees Celsius.

Example 15 (not according to the invention)

As in example 13.

50 kg of potash powder is mixed for 18 minutes at a mixing stage temperature of 85 degrees, rotor speed of 5 m/s, container speed of 1.4 m/s. Dry mixing: 1250 g of calcium oxide, 314 g of zinc oxide, 1159 g of zinc sulfate heptahydrate and 27.5 g of iron oxide are mixed for an additional 0.5 minutes at a rotor speed of 9 m/ s. In the wetting stage, 8 kg of water, 2.5 kg of potassium silicate are mixed for 0.5 minutes, and granulated at 1.5 minutes at a rotor speed of 27 m/s. Example 16 (not according to the invention)

Like example 15.

Dry additives: 1250 g of calcium oxide, 628 g of zinc oxide, 27.5 g of iron oxide. In the wetting stage, 8 kg of water, 2.5 kg of potassium silicate are mixed for 0.5 minutes, and granulated at 1.5 minutes at a rotor speed of 27 m/s.

Claims (1)

Granule comprising potash powder and a binder, wherein said binder is fly ash in a concentration of between 0.5-8% w/w and wherein said potash powder comprises particles with a size between 0.001-0 .5mm, wherein said granule also comprises polyhalite as an additive in a concentration of between 0.5 and 6% w/w. Procedure for the preparation of the granule according to claim 1, comprising: prepare fly ash as a binder; transferring said binder and polyhalite as an additive to a mixer and homogeneously mixing said binder and additive with a powdered potash feed to produce initial granules; transferring said initial granules to an agglomerator to produce agglomerates with a size ranging between 0.5 mm and 8 mm; transferring said agglomerates to a fluidized bed (FB) classifier to produce classified agglomerates; Dry the sorted agglomerates in a dryer and transfer them to a sieve to produce particles in 3 different size ranges: to. oversized particles having a diameter size of more than 6 mm; b. undersized particles having a diameter size below 1 mm; c. particles of desired size having a diameter size between 1 and 6 mm; introducing said undersized particles back into said powder feed; and crushing said oversized particles to provide ground particles wherein said ground particles are then sieved through said sieve. Method according to claim 2, wherein the preparation of said binder comprises the following steps: heating the binder, mixing, grinding, activation, dissolution and curing. Method according to claim 2, wherein said particles of desired size have a diameter size of between 2-4 mm.